#include <ros/ros.h>
#include <visualization_msgs/Marker.h>
#include <cmath>
int main( int argc, char** argv )
{
ros::init(argc, argv, "points_and_lines");
ros::NodeHandle n;
ros::Publisher marker_pub = n.advertise<visualization_msgs::Marker>("visualization_marker", 10);
ros::Rate r(30);
float f = 0.0;
while (ros::ok())
{
//创建一个 visualization_msgs/Marker消息，并且初始化所有共享的数据。消息成员默认为0，仅仅设置位姿成员w。
visualization_msgs::Marker points, line_strip, line_list;
points.header.frame_id = line_strip.header.frame_id = line_list.header.frame_id = "/my_frame";
points.header.stamp = line_strip.header.stamp = line_list.header.stamp = ros::Time::now();
points.ns = line_strip.ns = line_list.ns = "points_and_lines";
points.action = line_strip.action = line_list.action = visualization_msgs::Marker::ADD;
points.pose.orientation.w = line_strip.pose.orientation.w = line_list.pose.orientation.w = 1.0;
//分配三个不同的id到三个markers。points_and_lines名称空间的使用确保彼此不会相互冲突。
points.id = 0;
line_strip.id = 1;
line_list.id = 2;
//设置marker类型到 POINTS, LINE_STRIP 和 LINE_LIST
points.type = visualization_msgs::Marker::POINTS;
line_strip.type = visualization_msgs::Marker::LINE_STRIP;
line_list.type = visualization_msgs::Marker::LINE_LIST;
// scale成员对于这些marker类型是不同的,POINTS marker分别使用x和y作为宽和高，然而LINE_STRIP和LINE_LIST marker仅仅使用x，定义为线的宽度。单位是米。
points.scale.x = 0.2;
points.scale.y = 0.2;
// LINE_STRIP/LINE_LIST markers use only the x component of scale, for the line width
line_strip.scale.x = 0.1;
line_list.scale.x = 0.1;
// 点为绿色
points.color.g = 1.0f;
points.color.a = 1.0;
// Line strip 是蓝色
line_strip.color.b = 1.0;
line_strip.color.a = 1.0;
// Line list 为红色
line_list.color.r = 1.0;
line_list.color.a = 1.0;
//使用正弦和余弦生成螺旋结构。POINTS和LINE_STRIP markers都仅仅需要1个点作为每个顶点，然而LINE_LIST marker需要2个点 。
for (uint32_t i = 0; i < 100; ++i)
{
float y = 5 * sin(f + i / 100.0f * 2 * M_PI);
float z = 5 * cos(f + i / 100.0f * 2 * M_PI);
geometry_msgs::Point p;
p.x = (int32_t)i - 50;
p.y = y;
p.z = z;
points.points.push_back(p);
line_strip.points.push_back(p);
// The line list needs two points for each line
line_list.points.push_back(p);
p.z += 1.0;
line_list.points.push_back(p);
}
//发布各个markers
marker_pub.publish(points);
marker_pub.publish(line_strip);
marker_pub.publish(line_list);
r.sleep();
f += 0.04;
}
}
